How to use the elasticsearch2.helpers.BulkIndexError function in elasticsearch2

def bulk_update_cgm(cgms, actions=None, op='update', index=None):
    index = index or INDEX
    if not actions and cgms:
        actions = ({
            '_op_type': op,
            '_index': index,
            '_id': cgm._id,
            '_type': 'collectionSubmission',
            'doc': serialize_cgm(cgm),
            'doc_as_upsert': True,
        } for cgm in cgms)

    try:
        helpers.bulk(client(), actions or [], refresh=True, raise_on_error=False)
    except helpers.BulkIndexError as e:
        raise exceptions.BulkUpdateError(e.errors)